The present invention relates to a wall material made of vegetable materials such as soils, straws, chaffs, hemp, palms and the like.
In the past, walls of the wooden buildings in Japan are mainly formed in a so-called tuchi kabe (soil wall) type. In this type of wall, a nuki (a horizontal member that is arranged one upon the other in a space between columns having its opposite ends extended through columns) is provided as a support member, a komai (a member to be deployed as a bed of a wall) is formed using bamboos, woods, straw ropes and the like around an intermediate column which is erected between the nuki and a kneaded mixture of clays, straws, woods and the like is pasted on opposite surfaces of the komai to provide a bed wall, and after dried, mortars, sands and fiber materials are applied as a finish. Such so-called soil wall contains an innumerable micro pores in its surface and for this reason can serve to automatically control a room temperature and humidity in response to a varying atmospheric condition, and thereby providing a comfortable dwelling state and eliminating the chance of condensation occurring inside the wall and in an advantageous room even at an elevated temperature. Moreover, a heat insulating effect is provided so as to afford people the cool atmosphere in summer and a warm atmosphere in the winter. Furthermore, good soundproof and fireproof effects are provided. Thus, the soil wall was quite ideal meeting the Japanese weather and climate conditions.
However, the above-described wall was labor-intensive for its application and did not permit variations in the design of outer appearance. As a consequence, a number of so-called new building materials have been put on the market and used extensively in recent years.
Such new type wall materials have been adopted at an accelerated tempo in housing applications. These reasons include inter alia that the wall can provide more aesthetic appearance, is simpler to apply and more energy-efficient as a result of its superior heat insulating characteristics.
Despite their popularity, these new wall materials do not share certain benefits of the predecessors, result in problems which relate to lack of gas permeability and poor moisture absorption characteristics and therefore cause condensation to occur in the wall and on the wall surface in a room. The first problem is that moisture passes into the wall from below the floor and is confined in the wall as there is no outlet provided. This moisture evaporates and condenses upon a room temperature increasing or decreasing. Such evaporation or condensation is repeated, whereby significant damage is caused. This damage occurs both to the wall itself and to the major structural members of the building such as columns and sills. This damage may occur in a relatively short period. A lightweight foamed concrete which has attracted concerns in the industry is surely outstanding in its heat insulating effect, but it needs the coating of vinyl-based paints and the like to be applied over its outer surface to prevent the ingress of rain when applied as an outer wall. As a consequence, its inherent gas permeability is lost resulting in the problems described above.
In contrast, homes and other structures built using new building materials have rooms having a substantially improved heat-retaining effect for its improved air-tightness. However, such a room produces a tendency of moisture condensation on wall surfaces once the temperature drops, because its moisture content is not dissipiated easily. Under such a state, molds and fungus will grow easily and impose an adverse effect upon the health of people living in the structure. Over time the living environment of the people living in the structure is impaired and the comfort of the dwelling is lessened.
Furthermore, it is well-known that noise generated from adjacent house units in a collective housing arrangement such as town houses and the like result in social problems.
However, it has been difficult to provide a satisfactory solution to these problems so far.